Piezoelectric lighter

ABSTRACT

A CYLINDRICAL CASING HAS AN ANVIL IN ONE END HELD IN PLACE BY INWARDLY PROJECTING PORTIONS OF THE CASING. A PIEZOELECTRIC ELEMENT IN THE CASING ABUTS THE ANVIL AND HAS ITS ACTUATING PIN EXTENDING IN THE OTHER DIRECTION. A WASHER BEARING ON CASING PORTIONS AND A BELLEVILLE SPRING BETWEEN THE WASHER AND THE ELEMENT ENCIRCLE THE PIN AND URGE THE ELEMENT AGAINST THE ANVIL. A STRIKER HAS A HEAD AGAINST THE PIN AND A POST EXTENDING IN THE OTHER DIRECTION. A SPRING ENCIRCLES THE POST AND BEARS ON A DISC RESTRAINED BY THE CASING AND AGAINST THE HEAD TO URGE THE STRIKER TOWARDS THE PIN. THE OTHER END OF THE CASING FORMS A SAWTOOTH CAM ON WHICH RIDES A CAM FOLLOWER ATTACHED TO THE POST. THE CAM FOLLOWER IS CONNECTED TO A ROTATABLE CAP FOR ROTATION THEREWITH WHILE PERMITTING AXIAL MOVEMENT OF THE FOLLOWER IN THE CAP.

United States Patent [72] Inventors Dieter Westphal I Huckerswagen;

Gunter Mobus, Wermelskirchen. Germany [21] Appl. No. 864,806

[22] Filed Oct. 8, 1969 [45] Patented June 28,1971

[73] Assignee Joh. Vaillant, KG

Remscheid, Germany [32] Priority Oct. 19, 1968 [33] Germany {54]PIEZOELECTRIC LIGHTER 9 Claims, 6 Drawing Figs.

[52] U.S. Cl SIG/8.7, 317/79, 431/255 [51] lnt.Cl 110lv 7/00 [50] Fieldof Search 310/8],

[56] References Cited UNITED STATES PATENTS 3,428,408 2/1969 Ameyama eta1. 431/255 3,509,388 4/1970 Mifune et a1 310/8.7

Primary Examiner-D. F. Duggan Assistant Examiner-B. A. ReynoldsAttorney- Darbo, Robertson & Vandenburgh ABSTRACT: A cylindrical casinghas an anvil in one end held in place by inwardly projecting portions ofthe casing. A piezoelectric element in the casing abuts the anvil andhas its actuating pin extending in the other direction. A washer bearingon casing portions and a Belleville spring between the washer and theelement encircle the pin and urge the element against the anvil. Astriker has a head against the pin and a post extending in the otherdirection. A spring encircles the post and bears on a disc restrained bythe casing and against the head to urge the striker towards the pin. Theother end of the casing forms a sawtooth cam on which rides a camfollower attached to the post. The cam follower is connected to arotatable cap for rotation therewith while permitting axial movement ofthe follower in the cap.

PAT E NT EU JUN28 19?:

0/5751? I/VESTPHAL GUN TER M0505 IN VEN TORS BACKGROUND AND SUMMARY OFTHE INVENTION coupling, overcoming the action of a spring. When thespring is prestressed to a given extent, the coupling is released andthe striker engages the piezoelectric element. The coupling is aball-and-socket joint with a ballresiliently engaging in a groove in thestriker. The axial force spring tension) which i must be applied beforethe ball (detent) is forced back out of the groove depends on thegeometry of the relatively small ball and of the groove. Therefore,under ordinary manufacturing practices, it cannot be precisely defined.Also, strong contact pressures act on the detent and on the groove, sothat the coupling is subjected to considerable abrasion. Lastly, it ispossible to withdraw the manipulator only part way and then to let it gowithout releasing the coupling, so that the blow on the piezoelectricelement is weaker and one cannot tell whether or not an ignition sparkhas been produced. This can be a disadvantage in many cases. Moreover,all the spring force for prestressing the striker must be applied by theoperator directly and manually in an axial direction.

In another prior arrangement (Austrian Pat. No. 261,791), apiezoelectric element which is fixed relative to a casing is embraced atone end by a radially expansible, cup-shaped pressure sleeve and at theother by a cup-shaped striker. The

striker is biased by a first spring and has a radial flange on which theedge of the pressure sleeve comes to bear when pushed down in oppositionto the action of a second spring. When the pressure sleeve has pushedthe striker down to a certain extent and prestressed the first spring,it is expanded by means of inclined surfaces so that its edge slides offthe flange of the cup-shaped striker and the latter strikes thepiezoelectric elementunder the influence of the prestressed firstspring.

This prior arrangement is a very complicated design, with itspiezoelectric element mounted centrally in the casing and embraced fromboth ends. With this arrangement, too, the entire prestressing forcemust be applied directly and axially by the operator. To this force isadded the force required for radial expansion ofthe edges of thepressure sleeve.

The problem underlying the invention is that of creating a piezoelectriclighter which is both simple and strong in construction.

Another problem underlying the invention is that of creating apiezoelectric lighter which ensures that precisely defined blows willfall on the piezoelectric element.

A further problem underlying the invention is that of creating apiezoelectric lighter which requires relatively little force in order tooperate it.

A last problem underlying the invention is that of creating apiezoelectric lighter in which the striking mechanism may be aseparately manufactured unit.

In the present invention the manipulator is a rotatable control grip towhich the striker is connected in such a way that it is axially movablebut not rotatable with respect to the grip, and during its rotationalong with the grip the striker is axially moved by a follower ridingalong an extending sawtooth cam fixed relative to the casing.

The blow then falls in a precisely defined manner as the follower slipsdown over the steep edges of the sawtooth cam. The arrangement is verysimple and sturdy in construction, since it does not require eitherunreliable ball-and-socket joints or a central mounting for thepiezoelectric element. The

axial force for prestressing the spring acting on the striker isgenerated by way of the gently inclined surfaces of the sawtooth cam,and the manually exerted force may be further reduced by means of alever on the control grip if necessary.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal section through thepiezoelectric lighter;

FIG. 2 is a section along the line A-A of FIG. 1;

FIG. 3 illustrates the position of the lighter element in the casing bymeans of a section along the line B-B of FIG. 1;

FIG. 4 is a section along the line C-C of FIG. 1;

FIG. 5 is a partial section showing a part of the lower portion of FIG.I, seen in the direction D of FIG. 1; and

FIG. 6 is a diagrammatic illustration of the sawtooth cam developed in aplane.

DESCRIPTION OF A SPECIFIC EMBODIMENT The following disclosure is offeredfor public dissemination in return for the grant of a patent. Althoughit is detailed to ensure adequacy and aid understanding, this is notintended to prejudice that purpose of a patent which is to cover eachnew inventive concept therein no matter how others may later disguise itby variations in form or additions or further improvements. The claimsat the end hereof are intended as the chief aid toward this purpose, asit is these that meet the requirement of pointing out the parts,improvements, or combinations in which the inventive concepts are found.

A frame is formed by a casing l which is tubular in form and closed atone end by a cylindrical anvil 2. The anvil 2 has an annular groove 2',into which extend a plurality of casing portions 1' spaced around theperiphery of the casing. The anvil 2 also serves as the tool punchingdie for the cutting and stamping punches (not shown) which are appliedto the outside of the tubular casing l to force the projections 1 intogroove 2'. These punches cut the long sides of the casing portions 1 andat the same time press them into the annular groove 2' in the anvil 2during the manufacturing operation. The anvil is then fixed withoutclearance in the casing 1, in such a way that it cannot be displaced.

The piezoelectric element 4 bears on the anvil 2 by way of its foot 3.The element 4 has a square cross section (FIG. 3), and its four corners4 guide it in the casing l. A disc is held against movement away fromthe element by inwardly projecting projections 7 of the casing. ABelleville spring 5 bears on disc 6 and urges the element 4 against theanvil. The striker pin 8 of the lighter element 4 projects throughcentral openings in the disc 6 and spring 5.

The high-tension lead 9 runs from the side of the lighter element 4. Topermit the lighter element 4 to be inserted in the casing 1, the casing,if made from tubing, is slotted at 10 on one side. In the presentembodiment the casing l is made by forming a flat sheet into a tube. Theedges which then lie opposite one another are graduated in length, sothat, when bent into a tube, parts of them are about in contact (10 inFIG. 3) and parts form the slot 10 (FIGS. I and 2) for the shoe 9 of thecable 9.

When the striker head 12, which is biased by the coil spring 11, is inits position of rest, it bears on the element pin 8. The spring 11biasing the striker is supported at its other end on a disc 14. Disc 14in turn bears on inwardly extending stamped out portions 15 of thecasing l. The rotatable control grip 16 is fixed to the disc 14. Thisgrip comprises an outer, cup-shaped sleeve I6 and two abutments 16"(FIG. 4) which are symmetrically positioned relative to one another. Theabutments are secured to the base of the sleeve 16'. They aresemi-cylindrical and define a gap 16" between them. Advantageously, thegrip l6 and its elements 16 are made in one piece from a syntheticplastic material. At their distal ends, the abutments 16" have integralposts 17 (FIG. 5), which extend through two symmetrically positionedholes in the disc 14. The ends of posts 17 are hot worked to formrivet-head-like portions 17.

After insertion of the coil spring 11, the post 12' of the striker 12 ispassed through the opening opening 13 in the disc 14 until it projectsinto the rotatable grip 16. The post 12' is then twisted so that theopening 12" adjacent its end is flush with the gap 16. The crosspin 18(a slotted pin) is then pushed into the opening 12". All the componentsof the striking mechanism 19 are now connected together to form a singlestructural unit.

That end of the casing which serves to receive the striking mechanism 19forms a sawtooth cam comprising cam surfaces 21 inclined with respect tothe axis of the casing and edges 22 parallel to said axis. The inclinedsurfaces 21 are joined to edges 22 at outwardly extending noses of thecam. The surfaces 21 and the edges 22 lie opposite one another,respectively, on the tubular end of the casing, i.e. there are twosurfaces 21 which are 180 apart.

In assembly, the striking and manipulator mechanism 19 is introducedinto the casing 1 until the striker head 12 bears on the element pin 8.With the spring 11 in place, the disc 14(already secured to cap 16) isplaced over post 12' and pin 18 (forming a cam follower) is insertedthrough the post. The disc is then pushed in until it reaches itsassembled position. The prepared casing portions are then pushed fromoutside into the bearing groove 15 formed by the disc 14 and byshoulders 16"" on the abutments 16". The disc 14 is now supported, andthe grip 16 can rotate in this bearing without moving axially.

To produce a piezoelectric ignition spark, the rotatable control grip 16is turned. The turning of the control grip rotates pin 18 relative tocasing l. The grip can turn in one direction only: the direction inwhich the follower 18 moves up the inclined surface 21 (downwardly inFIG. 1). Upon reaching the outwardly extending noses of the cam wherethe surfaces 21 join the edges 22, the follower 18 is free to return inan axial direction allowing striker 12, 12 to be forced against pin 8 byspring 11. As a result of the force of the coil spring 11, the strikerhead 12 impacts against pin 8 of the lighter element 4. The high tensionpassed to the spark gap along the lead 9 produces an ignition spark. Toproduce another ignition spark, the control knob is again turned in thesame direction.

We claim:

1. In a piezoelectric lighter comprising a piezoelectric element memberand a striker member, a frame, one of the members being movably mountedon the frame for movement toward and away from the other member, and aspring resiliently urging the one member toward the other member, theimprovement comprising:

said frame being in the form of a tubular casing having two ends and anaxis between the ends, said other member being within said casing andadjacent one end of the easing, said one member being within said casingand between the other member and the other end of the easing, saidspring being within the casing and at least partially between said onemember and the other end of the casing, said other end of the casingdefining a sawtooth cam having first edges inclined with respect to saidaxis and second edges substantially parallel to said axis, cam followermeans secured to said one member and contacting said cam for moving saidone member away from the other member against the urging of said springas the follower means is rotated with respect to said casing andthereafter releasing said one member for movement toward the othermember by said urging, and a cap about said other end of said casing,rotatable with respect thereto and operatively connected to said camfollower means for rotating the cam follower means.

2. In a lighter as set forth in claim 1, wherein said cap has two spacedsemicylindrical abutments positioned within said other end of saidcasing, said follower means including a pin normal to said axis,connected to said one member and positioned in said cap in the spacebetween said abutments.

3. In a lighter as set forth in claim 2, wherein said cam has two ofsaid inclined surfaces spaced about said axis apart. 4. In a lighter asset forth in claim 2, wherein said abutments have posts at the distalend thereof which posts project into said casing parallel to said axis,a disc attached to the distal end of the posts, said disc having acentral opening, said cam follower means comprising a post extendingthrough said spring and opening, said pin being attached to the latterpost adjacent the distal end thereof, said casing having inwardlyprojecting portions between said disc and the distal ends of theabutments to restrict said cap against axial movement while allowingrotational movement thereof.

5. In a lighter as set forth in claim 4, wherein said one member is thestriker member, and including an anvil in said casing at said one endthereof, said anvil having an annular groove therein, said casing havinginwardly projecting portions extending into said annular groove to locksaid anvil to the casing against axial movement, said element memberabutting said anvil.

6. In a lighter as set forth in claim 5, wherein said element memberincludes an actuating pin extending from the end thereof adjacent saidstriker member, said frame includes a second disc having a centralopening, said second disc being positioned in said casing between saidstriker member and element member with said pin extending through saidcentral opening therein, said casing having inwardly projecting portionsagainst which said second disc seats and restrains movement of thesecond disc in a direction away from said element member, and aBelleville spring between said second disc and said element member.

7. In a lighter as set forth in claim 1, wherein said one member is saidstriker member, and including an anvil in said casing at said one endthereof, said anvil having an annular groove therein, said casing havinginwardly projecting portions extending into said annular groove to locksaid anvil to the casing against axial movement, said element memberabutting said anvil.

8. In a lighter as set forth in claim 7, wherein said element memberincludes an actuating pin extending from the end thereof adjacent saidstriker member, said frame includes a disc having a central opening,said disc being positioned in said casing between said striker memberand element member with said pin extending through said central openingtherein, said casing having inwardly projecting portions against whichsaid disc seats and restrains movement of the disc in a direction awayfrom said element member, and a Belleville spring between said disc andsaid element member.

9. In a lighter as set forth in claim ll, wherein said element memberincludes an actuating pin extending from the end thereof adjacent saidstriker member, said frame includes a disc having a central opening,said disc being positioned in said casing between said striker memberand element member with said pin extending through said central openingtherein, said casing having inwardly projecting portions against whichsaid disc seats and restrains movement of the disc in a direction awayfrom said element member, and a Belleville spring between said disc andsaid element member.

